Your Air: Key Findings

Overall, air in the Westside community meets health-based standards because the air quality has been in attainment since 2005. EPA uses the term "attainment" when the levels of air pollution are at or below the air quality standards known as National Ambient Air Quality Standards or (NAAQS).

Benzene was an issue in the past; however, it is no longer an issue and Texas Commission on Environmental Quality (TCEQ) is monitoring benzene levels in the area.

Port Arthur Environmental Profile

Beginning in the 1970s, EPA developed the National Ambient Air Quality Standards (NAAQS) for six common air pollutants that pose serious effects to human health and the environment: carbon monoxide (CO), lead (Pb), nitrogen oxides (NOx), ozone (O3), airborne liquid and solid particles (known as particulate matter or PM2.5 and PM10), and sulfur dioxide (SO2). EPA often refers to these pollutants as "criteria pollutants" because allowed levels are set using human health or environmental criteria.

There are 5 air monitoring sites in the Port Arthur area that are designed to monitor weather conditions and collect data for air pollutants. Three of those five monitoring stations monitor for hazardous air pollutants such as benzene (VOCs) typical of refinery emissions. The map and key show the location of various monitors and what pollutants each monitor is designed to measure.

Air monitoring stations in Port Arthur

Air Pollutants

Overall, the air quality is in good condition. EPA monitoring results have indicated that one contaminant, ozone, is not within guidelines; therefore, caution is advised. In-frequently, but on fewer days than the ozone standards allows, the ozone value has exceeded the standard for sensitive groups. Ozone was not rated as a red, in the chart below, since the excedences were limited, and impacts can be mitigated by such things as avoiding strenuous activity outdoors.

Potential Impacts from Air Pollutants

Air Pollutant

Current Status

Ozone Current Standard

OK, No known concerns

Ozone Delayed Standard

Caution is Advised (condition may be temporary)

Particulate Matter Course (PM10)

OK, No known concerns

Particulate Matter Fine (PM2.5) Current & Proposed

OK, No known concerns

Nitrous Oxides (NO2)

OK, No known concerns

Sulfur Dioxide (SO2) 24 Hour Standard

OK, No known concerns

Sulfur Dioxide (SO2) 1 Hour Standard

OK, No known concerns

The Sulfur Dioxide 1 hour standard was violated for the rolling three year period ending in 2009, and just met the standard (rounded down) in 2010.

Hazardous Air Pollutants

Hazardous air pollutants (HAPs) are also known as toxic air pollutants or air toxics. They are pollutants that cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological effects. EPA and TCEQ track HAPs released into the air through permits, monitoring stations, and modeling. Examples of HAPs include benzene, which is found in gasoline; perchlorethlyene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries.

Air Modeling: Air modeling is a method that often uses computers to run calculations that imitate the air space over an area. The air models can be used to predict the air quality and levels of pollution in the air and the amounts that might be deposited on the ground. Air modeling results are used to focus enforcement inspections on specific equipment and specific chemicals.

Potential Impacts from Hazardous Air Pollutants

Area of Influence

Current Status

Community Monitors - Annual Average Concentrations

Pollutants such as Benzene are below State screening levels.

Modeled Risk Past Fenceline

EPA Modeling "Regional Air Impacts Modeling Initiative" (RAIMI) indicates risk in the middle to upper range of EPA's acceptable risk for long term effects.

Past Fenceline - Exceptional Accidents

Large episodic releases due to accidents, power outages, etc. may result in shelter-in-place events.

Studying the effects of air pollutants

The maps below show results of multi-facility risk modeling. Emission sources from 15 different facilities were included in this modeling effort. The model takes into account local wind patterns and other factors that impact how air pollutants move. The modeled risk is "cumulative" in that all sources of known pollution are included. The model relies on emission inventory data reported by industry to the TCEQ. The orange dots on the map each represent a source of pollutants (for example, a tank, flare, or process unit) reported to the TCEQ that were included in the model. It is important to note since this is cumulative modeling as impacted by meteorology, that a particular color on the map does not necessarily correspond to a source at that particular location. For example, although Chevron Phillips is West of the intersection of the State HWY 214 Spur and State HWY 87, it's individual contribution to the total cumulative risk calculated for that area is minor.

The modeled cancer risk (probability of contracting cancer due to breathing cancer-causing pollutants) and non-cancer health risks is divided into three colors. The orange dots represent a source of pollutants, the purple areas represent areas with the highest modeled risk, and the blue areas the lowest. EPA generally focuses attention on areas where the cancer risk exceeds a probability of one excess cancer (above background) for every 10,000 individuals exposed (1E 10-4) over a 70-year period of exposure. That is the high end of EPA's acceptable cancer risk range. As this map shows, the purple colored areas, representing the highest modeled risk probabilities, are at the high end of EPA's acceptable risk range; and the blue colored areas are in the low to mid ranges of EPA's acceptable risk range for cancer. For non-cancer health risks, the purple colored areas slightly exceed EPA's target level for safety.